Run your favorite 31.8mm clamping diameter handlebar on a bike with Knock Block with the Rhythm Comp 31.8. It adds Knock Block compatibility to a durable stem with multiple lengths to let you fine-tune the fit to your ride.
Get 31.8mm handlebar compatibility with your Knock Block system;Also compatible with standard headsets and spacers;Knock Block system protects frame from impacts by fork and handlebars by eliminating over-rotation of bars;Available in a wide range of sizes for today's mountain rider;See Service Parts for other Knock Block parts;

The Madone is built as a seamlessly integrated machine designed to do one thing: go fast. Trek's Madone Integrated Bar/Stem is an important part of that integration. Available in a variety or widths and reaches so you can dial in your superbike specifically for you.
- Compatible with model year 2016/17 Madone
- Variable radius, compact flare (VR-CF) shape offers wrist clearance in the drops
- 100% OCLV carbon fiber construction
- Seamless accessory integration with Blendr
- Blendr accessory bases and mounts sold separately